Characters as Adaptive and Specific. 245 



in producing " blastogenetic species" by artificial 

 changes of environment. Or, as Ray Lankester has 

 well stated this consideration, " It is not difficult to 

 suggest possible ways in which the changed con- 

 ditions, shown to be important by Darwin, could act 

 through the parental body upon the nuclear matter 

 of the egg-cell and sperm-cell, with its immensely 

 complex and therefore unstable constitution. . . . The 

 wonder is, not that [blastogenetic] variation occurs, 

 but that it is not excessive and monstrous in every 

 product of fertilization V 



If to this it should be objected that, as a matter 

 of fact, experimentalists have not been nearly so 

 successful in producing congenital modifications of 

 type by changed conditions of life as they have been 

 in thus producing merely somatic modifications ; or if it 

 should be further objected that we have no evidence 

 at all in nature of a " blastogenetic species " having 

 been formed by means of climatic influences alone, 

 if these objections were to be raised, they would admit 

 of the following answer. 



With regard to experiments, so few have thus far 

 been made upon the subject, that objections founded 

 on their negative results do not carry much weight 

 especially when we remember that these results have 

 not been uniformly negative, but sometimes positive, 

 as shown in Chapter VI. With regard to plants and 

 animals in a state of nature, the objection is wholly 

 futile, for the simple reason that in as many cases as 

 changed conditions of life may have caused an here- 

 ditary change of specific type, there is now no means 



1 Nature, Dec. ia, 1889, p. 129. 



